Air / fuel mixture screw O-ring

Hi i have been having problems with my XJ650 having rich sooty sparkplugs for many months now, resulting in many costly “buys” i never really needed. Today i change the tiny O-ring inside the fuel/air mixture screw just for the fun of it (lockdown/quarantine etc) and with on click wow its like a new engine entirely, i never thought such a tiny O-ring would have that much effect.. after 30pcs. Of new NgK’s dozens of shims etc. it only took 2US dollars worth of oring to fix my carbs WOW thanks santa!

 

No more gasoline smell from exhaust... very crispy response!

 

tiny but importan to replace this oring. it seals off the mixture screw from the threaded portion of the mixture screw. even the washer above it may need replacing

 

How did they look before replacing them ,is the old one the one on the right ?

 

Both of those are new parts. The washer on the left, and the o-ring on the right.
Though at least one (I suspect the washer) is not exactly the right size.

 

i used the wrong type (to small) when i first cleaned the carbs, i never thought i would matter much since there was a washer then a spring then a threaded nut on top of it.

 

the old ones looked very "new" i guest it was to small compared to the original and only sat there not doing any "sealing job" i think there should be some deformation if it was doing its job down there

 

i just fitted a full keyster rebuild kit to my 81 xj650, I lost one of the idle screws, and was in the mood for a pending spree...
imagine my sad expression when the new screws would not screw in - the threads are much finer. I have sent a message to the vendor, but I think I need a plan B which is to ask around here and see if someone has a spare.....
I could fully dismantle the shed and put everything on the lawn so I can conduct a fingertip search but its just started snowing........
will try to upload a pic